Oral tolerization with self antigens to induce active suppression is a therapeutic approach to the treatment of human inflammatory autoimmune disorders. Regulatory T cells mediate active suppression by secretion of suppressive and anti-inflammatory cytokines such as IL-4, IL-10 and TGF- Beta 1 which are induced by the oral toleragen. The dose of oral antigen administered is critical in triggering the active form of peripheral immune tolerace which displays a complex, although diagnostic, cytokine expression pattern. In Phase I of this proposal we will demonstrate the feasibility of designing and using high density oligonucleotide arrays for the sensitive and quantitative detection of multiple cytokine messages in parallel. We will employ these arrays to monitor various cytokine mRNAs as phenotypic markers in a transgenic mouse model of autoimmunity and oral tolerance. During Phase ll will extend our study to the detection of human cytokine messages and investigate the potential application of high density oligonucleotide arrays to the monitoring of Th1, Th2 and Th2-like cytokine profiles in human autoimmune inflammatory disease, and its treatment by administration of oral antigen. The ability to measure levels of regulatory T cells that mediate active suppression using high density oligonucleotide arrays could enable healthcare professionals to provide better patient management in treatment for autoimmune and cell-mediated inflammatory diseases. PROPOSED COMMERCIAL APPLICATION: The ability to measure cytokine levels of regulatory T cells using high density oligonucleotide arrays has a clear commercial application in the treatment of autoimmune inflammatory diseases by oral tolerance. The mechanism of suppression by specific regulatory T cells depends on the dosage of oral antigen administered and is associated with a specific pattern of cytokine expression (3,4,24). Currently, there are a number of human clinical trails using orally administered drugs to treat autoimmune diseases (16,22,24). Given the dose dependent response of oral therapy, using specific cytokine profiles as diagnostic markers of induced peripheral tolerance may be important to healthcare providers for proper patient management.